Metabolic Flexibility: A Fullscript Forward Preview

Oct 9, 2025

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If metabolic flexibility is the key to longevity, are we missing critical opportunities to help our patients achieve it?

In this episode of The Root Cause Medicine Podcast, we sit down with Dr. Rob Downey and Monique Class, two respected functional medicine clinicians presenting at Fullscript Forward 2025, to explore how precision approaches to metabolic health are reshaping longevity care. Dr. Downey reveals how metabolic phenotyping, stress and HRV mapping, and gut function insights can inform individualized care strategies, while Monique shares her thoughtful approach to microdosed GLP-1 protocols, titration by response, and slow tapering models designed to complement lifestyle-first interventions. Together, they unpack the art and science of whole-person metabolic medicine—covering body composition tracking, lab-based decision-making, and muscle-preserving movement routines that clinicians can integrate into real-world workflows.

If you’re ready to help your clients achieve true metabolic transformation, this episode offers the frameworks, data points, and clinical pearls you won’t want to miss.

Clinical Takeaways from This Episode

Metabolic Phenotyping & Personalized Patterns in Longevity Care: Dr. Downey discusses using patterns such as body shape, lifestyle context, and lab trends to categorize presentations and organize evaluation, rather than applying one standardized protocol to everyone.
“Body-Knows-the-Way” Framing & Foundational Inputs: Both Dr. Downey and Monique Class describe a model focused on reducing burdens (e.g., chronic stress, inflammation, dysbiosis) and adding supports (sleep, whole foods, movement) so adaptive pathways may function more effectively.
Stress Physiology, HRV, Sleep & Behavior Change: Conversation covers the role of chronic sympathetic arousal and low HRV in metabolic challenges, and how breath work, meditation, or similar practices were used by some patients in their experience to shift autonomic balance.
GLP-1 Microdosing, Titration & Slow Tapering: Monique explains her rationale for starting below common starter doses when appropriate, titrating to the lowest perceived effective dose to reduce “food noise,” and planning tapering from the outset—positioning medications as a potential bridge during lifestyle change.
Side-Effect Themes & Constipation Workflow on GLP-1s: Both practitioners review proactive steps they consider before initiation of GLP-1s, such as addressing reflux/constipation and dysbiosis, and discussed tools often used in practice (hydration strategies; magnesium citrate/Cal-Mag; buffered vitamin C; ginger/bitters; gradual fiber; stool positioning) to manage common GI complaints.
Nutrition Patterns, Endogenous GLP-1 Signaling & Glycemic Awareness: The dialogue highlights food-quality patterns (protein with meals; colorful produce; fermented foods/fiber) discussed in relation to satiety, SCFA production, and L-cell signaling, as well as interest in meal timing and CGM-based learning.
Muscle Preservation & Body Composition Tracking: Monique and Dr. Downey discuss prioritizing resistance training, NEAT/micromovement, and tracking lean mass vs. visceral fat (e.g., Seca metrics, phase angle) as more informative than scale weight alone.
Medication Reviews During Weight Loss: The guests emphasized reviewing other medications (e.g., blood pressure, lipid, glycemic, or psychiatric medications) as weight, intake, and vital signs change, with attention to orthostasis or hypoglycemia risk.
Gut–Brain–Metabolic Axis Considerations: Guests describe empiric GI support and, in some cases, stool testing, as well as nutrients like glutamine and zinc (including zinc carnosine)in the context of comfort and barrier support.
Metabolic Rebound & Relapse Prevention: The conversation covers reports of rebound with rapid dose escalation/high doses and abrupt discontinuation, and discussed slower titration, gradual tapering, and habit “scaffolding” (meal timing, movement, sleep, alcohol awareness) as strategies they consider to help maintain gains.

Guest Bios

Dr. Rob Downey, MD, IFMCP — Functional medicine physician at Seaworthy Medicine (AK); discussed phenotyping, HRV/stress context, and gut-metabolic foundations in complex cases.

Monique Class, FNP, IFMCP — Family nurse practitioner with 35+ years in functional medicine; discussed GLP-1 microdosing, tapering/off-ramps, and whole-person frameworks for weight management, inflammation, and longevity.

Labs Mentioned (Monitoring & Context)

Glycemic/insulin markers: Fasting insulin, fasting glucose, HbA1c, optional CGM patterns
Lipid & metabolic context: Standard lipid panel; triglycerides; uric acid; waist circumference
Endocrine/sex hormones: Thyroid panel; sex hormones as indicated
GI & micronutrients: Stool testing where applicable; micronutrient analyses
Body composition: Visceral fat and phase angle (e.g., Seca), lean mass vs. fat mass

Ingredients & Therapeutic Nutrition Mentioned

Gut/immune: Boswellia, bromelain, quercetin; probiotics (product/strain selection varies)
Stress/adaptogens: Ashwagandha, cordyceps, phosphatidylserine; ginseng/licorice when appropriate
Metabolic support: Chromium, bitter melon; glutamine, zinc / zinc carnosine, lecithin
Constipation toolkit: Magnesium citrate or Cal-Mag, buffered vitamin C, ginger/bitters, aloe options, gradual fiber, hydration, stool positioning

Diet patterns referenced: Protein at meals, fermented foods, colorful produce, structured meal timing, mindful alcohol intake

Fullscript Forward Details

Fullscript Forward Summit – Oct 17 → https://www.fullscriptforward.com/

Timestamps

00:00 Intro & Fullscript Forward overview
01:54 Guest intros
03:15 Downey’s journey: autoimmunity → metabolic health focus
10:20 Phenotype & hormonal pattern assessment
13:18 Sequencing foundational interventions before advanced steps
15:39 Labs for assessing metabolism
19:22 GLP-1 tapering and off-ramp planning
22:26 Small-dose GLP-1 protocols & titration discussion
30:31 Metabolic rebound: drivers & mitigation approaches
43:03 Whole-person care & healthspan goals

Frequently Asked Questions

Q: What makes this episode different from other GLP-1 discussions?
Most conversations stop at dosing. This one goes further—into phenotyping, nutrient status, and tapering protocols that integrate lifestyle medicine. It’s about how to use GLP-1s thoughtfully within a personalized, long-term metabolic framework.

Q: What is “metabolic phenotyping,” and why does it matter?
Dr. Downey explains how identifying phenotype patterns—such as stress physiology, body composition, and gut-driven inflammation—can help clinicians prioritize interventions and understand why certain patients plateau despite doing “everything right.”

Q: What key labs and metrics do the guests discuss?
They review labs that provide insight into insulin sensitivity, thyroid health, inflammation, and micronutrient status, as well as body composition measures (like visceral fat and phase angle) that reveal metabolic trends beyond weight alone.

Q: What can providers take away from this conversation?
A clearer view of how to connect physiology, psychology, and behavior change in metabolic medicine—plus practical insight into tapering, monitoring, and optimizing care over time.

Q: Who should listen to this episode?
Healthcare professionals interested in functional and lifestyle medicine, longevity, or integrative metabolic care—particularly those seeking to bridge the gap between pharmacology and personalized nutrition.

Disclaimer: The views expressed on this podcast are those of the hosts and guests and don’t necessarily reflect those of Fullscript or any affiliated organizations. This podcast is for informational and educational purposes only and is not intended to be medical advice. For your safety, always check with your doctor or healthcare provider before making changes to your health routine.